The way we communicate at work, at home, and while traveling is beginning to change significantly once again. Users are hungry for new converged Internet Protocol (IP) multimedia services driven by new user devices and the wider availability of broadband access networks. Many users want to be able to access a common set of services independent of how or where they initiate or receive a communication. New and traditional service providers are anxious to create offers with exciting new capabilities that use the innovative Internet paradigm to create converged voice, data, and video services. While many protocols will be used in next-generation communications networks, the Session initiation protocol (SIP) stands at the center of the new communications paradigm and is widely recognized as the primary communications protocol in evolving and next-generation networks.